code: def gen_block(num_rows):
      return pa.table({"foo": [1] * num_rows})
  
file_path: ray/python/ray/data/tests/test_batcher.py
imports: import time
  import pyarrow
  import pytest
  import ray
  from ray.data._internal.batcher import Batcher, ShufflingBatcher
label_desc: Use image node_id 1 for calling a global function with example usage: gen_block(num_rows) and returns: pa